JPH0510498B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a fuel supply system for an internal combustion engine, and more particularly to a dual system fuel system that can be operated to supply two different types of fuel to a single internal combustion engine.

A dual-line fuel supply system selectively supplies expensive fuel, such as gasoline, to the internal combustion engine during starting, idling, and low-speed operation, and supplies less expensive fuel, such as kerosene, to the internal combustion engine during low and normal speed operation. It is known that it can provide cheap fuel.

Conventional dual system fuel systems are described in the following US patents: US Pat.

Patent Holder Patent Number Date of Issue Bartholomew 2616404 November 4, 1952 Meyer et al. 2643647 June 30, 1953 Anderson 2664871 January 5, 1954 Boyce 4056087 November 1, 1977 Etoh 4085720 April 25, 1978 Itoh et al. 4090484 May 23, 1978 Etoh 4129620 December 12, 1978 Attention is also drawn to British Patent No. 644721, issued October 18, 1950. Further, Billingpley dated August 4, 1980.
Attention is also drawn to patent application Ser. No. 175,348 to Haman et al., and patent application No. 406,446 to Haman et al.
These have been assigned to the assignee of this application.

In this type of device, in addition to the primary fuel supply in a low pressure zone formed in the fuel/air induction passage, a secondary orifice communicating with the fuel/air induction passage is provided at a location downstream of the low pressure zone; A low-pressure zone is supplied with a cheap but low-volatility primary fuel such as kerosene, and a secondary orifice is supplied with an expensive but highly volatile secondary fuel such as gasoline. It's summery.

In such devices, when the internal combustion engine is idling, the throttle valve is closed and the secondary orifice must supply a sufficient amount of fuel to rotate the internal combustion engine. Since this supply continues as it is even if the rotation of the internal combustion engine increases, the second fuel, which is expensive, is consumed and is not economical.

For this reason, devices have been developed that are equipped with means to automatically cut off the supply of the second fuel when the rotation of the internal combustion engine becomes higher than idling, but the mechanism for this is inevitably complicated.

The purpose of the present invention is to
An object of the present invention is to provide a two-type fuel supply device capable of reducing consumption of a second fuel.

The inventor of the present invention confirmed that the desired effect can be achieved even if the second fuel is not supplied entirely from the secondary orifice, and in order to achieve the above object, the first fuel supply The apparatus includes a device operable to simultaneously supply the first fuel to the secondary orifice without passing through the secondary orifice; The configuration includes a device operable to supply the second fuel to the secondary orifice at the same time as supplying the second fuel to the secondary orifice.

With this configuration, the fuel/air induction passage is always supplied with the first and second fuels from the secondary orifice, and the consumption of the second fuel can be minimized.

The two types of fuel supply device of the present invention further includes a second fuel inlet in the low pressure zone downstream of the secondary orifice and the throttle valve, and from the inlet to the induction passage,
The configuration includes a priming pump that selectively introduces a controlled amount of the second fuel.

With this configuration, only the second fuel can be reliably supplied to the low pressure zone in a controlled amount and only at selected times.

Other features, aspects, and benefits of the invention will become apparent to those skilled in the art from consideration of the following detailed description, drawings, and claims.

Before describing in detail at least one embodiment of the invention, it is understood that the invention is not limited in application to the detailed construction and arrangement of elements set forth in the following description and drawings. Should. The invention is capable of other embodiments and of being practiced and carried out in various ways. It should also be understood that the words and terminology used in the text are for descriptive purposes only and should not be considered limiting.

What is shown in the drawing is a fuel supply system 10 for an internal combustion engine (not shown) installed in an outboard motor or the like.
It is. The fuel supply system 10 is configured to operate the engine using two different types of fuel, for example an inexpensive primary fuel such as kerosene and an expensive secondary fuel such as gasoline. It is located in This device is arranged to supply a mixture of two types of fuel to the engine during idling as well as during low speed and normal speed operation. The device also has an arrangement that allows secondary fuel to be primed or started so that the engine can be easily started.

Fuel supply system 10 includes a carburetor 12 having a fuel/air induction passage 14 communicating with an engine fuel intake (not shown). The fuel/air induction passage 14 includes a vent 16 having a throat defining a low pressure zone 18 . Downstream of the ventilate 16 is a throttle valve movable between open and closed positions to regulate the flow of fuel and air through the fuel/air induction passage 14, thereby regulating engine speed. 20 are installed.

The wall of the fuel/air induction passage 14 adjacent to the periphery of the throttle valve 20 is provided with one or more secondary orifices 2.
2 are arranged, and each orifice is connected to a vaporizer 12.
It communicates with a fuel cavity or well 24 within. The carburetor 12 includes a fuel duct or passage 26 through which fuel is supplied to the cavity 24 . The flow of fuel into cavity 24 through the fuel passage is regulated by needle valve 28.

The carburetor 12 includes a first or primary fuel chamber or float bowl 30 . A primary fuel, such as kerosene, is supplied to float bowl 30 from a primary fuel source 31 by an inlet hose or conduit 32 and a fuel pump 33 or other suitable device.

The flow rate of the primary fuel into the float bowl 30 is regulated by a float regulating valve 34 connected to the float 36 and opened and closed according to the movement of the float 36. Thus, valve 34 and float 36 serve to maintain a predetermined level of primary fuel within float bowl 30.

The vaporizer 12 is provided with a full-time hole 37,
Through this, the float bowl 30 communicates with the atmosphere.

The primary fuel is the float bowl 30 and the low pressure zone 18
The low pressure zone 18 is supplied from the float bowl 30 through a fuel nozzle 38 extending between the float bowl 30 and the fuel nozzle 38 .
More specifically, the carburetor 12 has a normal fuel level 4.
A depending hollow boss 40 having a lower end below 2 and extending into the float bowl 30 is provided. The lower end of this boss 40 is closed by an orifice plug 44 and the fuel nozzle 38 extends into the boss 40 on the orifice plug 44. vaporizer 1
2 also includes a needle valve 45 that regulates the fuel flow from the float bowl 30 to the fuel plug.

The primary fuel is supplied to the float bowl 30 and the fuel passage 2.
The fuel passageway 26 is supplied from the float bowl 30 by a pick-up conduit or tube 46 extending between the float bowl 30 and the fuel passageway 26. In this way, the pick-up conduit 46 and the fuel passage 26 allow the float ball 3
A conduit connecting 0 to cavity 24 is formed. Although other arrangements may be used, in the particular configuration shown, the pick-up tube 46 is disposed inside the fuel nozzle 38 with an annular flow path 49 defined therebetween.

The fuel supply system also includes a housing having a secondary fuel chamber or float bowl 52. A secondary fuel, such as gasoline, is supplied to float bowl 52 from a secondary fuel source 54 by an inlet hose or conduit 56 and a fuel pump 58 or other suitable device. The flow rate of the secondary fuel to the float bowl 52 is controlled by a float regulating valve 60 that is connected to the float 62 and opens and closes according to the movement of the float 62.
Adjusted by. In this manner, valve 60 and float 62 maintain a predetermined level of secondary fuel within float bowl 52.

A vent hole 63 is provided at the top of the housing 50, through which the float bowl 52 communicates with the atmosphere.

The secondary fuel is connected to an outlet 66 within the housing 50;
The fuel passageway 26 is supplied from the float bowl 52 by a tube or conduit 64 extending between the fuel passageway 26 and a fuel inlet 68 on the carburetor 12 that communicates with the fuel passageway 26 . The orifice 70 in the fuel intake port 68 is connected to the fuel passage 2 for the secondary fuel.
Limit the flow to 6.

The fuel supply system 10 may also include a conventional plunger-type prime pump 72 for supplying a small amount of secondary fuel to the fuel/air induction passageway to facilitate engine starting. The priming pump 72 is connected in communication with an external stem 74 , an inlet 76 in communication with the housing outlet 66 by a tube or conduit 78 , and in communication with the fuel/air induction passage 14 by a tube or conduit 82 . and an outlet 80. Although the prime fuel can be introduced into the fuel/air induction passage 14 in a variety of configurations, in the particular configuration illustrated, the fuel/air induction passageway 14 is
A fuel inlet 84 communicating with the air induction passage 14 is arranged downstream of the throttle valve 20 and a conduit 82 is connected to the fuel inlet 84 .

If kerosene and gasoline are used as the primary and secondary fuels, respectively, pushing the stem 74 down onto the priming pump 72 can provide priming to facilitate engine starting. As a result, a constant flow rate of gasoline is supplied from the float chamber 52 to the fuel/air induction passage 18 through the fuel inlet 84.

When the engine is started, during startup or normal operation, the flow of gasoline is from the float bowl 52 to the cavity 24 through the fuel passage 26 and into the cavity 24.
4 through a secondary orifice 22 to a fuel/air induction passageway. At the same time, a flow of kerosene is directed from float bowl 30 through pick-up tube 46 and fuel passage 26 to cavity 24, and from cavity 24 (after mixing or blending with gasoline) through a secondary orifice to fuel/air induction passage 18. Ru. At the same time, the flow of kerosene is directed from the float chamber 30 through the annular passage 46 between the pick-up pipe 46 and the fuel nozzle 38 to the low pressure zone 30.
You will be guided to 8. In this way, once the engine is started, the primary fuel (kerosene) and the secondary fuel are mixed during idling, partial throttling, and full throttle operation.

This mixture allows the engine to operate with less expensive secondary fuel, compared to traditional dual fuel systems that use only secondary fuel during starting and/or idling. The mixing ratio of the mixed fuel in the cavity that reduces operating costs depends on the flow resistance in the primary and secondary fuel systems between the fuel well and each float chamber.

Various features of the invention are set out in the claims.

[Brief explanation of drawings]

The accompanying figures are schematic illustrations of dual fuel supply systems embodying various features of the present invention. 10... fuel supply device, 12... carburetor, 14
...Fuel/air induction passage, 18...Low pressure zone, 22
... Secondary orifice, 24 ... Cavity, 30 ... First float bowl, 31 ... First fuel source, 3
4...First valve, 38...Fuel nozzle, 52...
Second float bowl, 60...valve, 72...priming pump, 76...inlet, 80...outlet, 8
4... Fuel inlet.

Claims (1)

Claims: 1. A fuel/air induction passage 14 with a device defining a low pressure zone 18, a throttle valve 20 disposed downstream of said low pressure zone 18, a fuel/air induction passage 14 having a device defining a low pressure zone 18, a throttle valve 20 disposed downstream of said low pressure zone 18; Secondary orifice 2 communicating with the induction passage
2, and a carburetor comprising a fuel inlet 84 disposed downstream of the secondary orifice and the throttle valve and communicating with the air induction passage 14;
a first fuel source 31 and comprising a device operable to simultaneously supply first fuel to said secondary orifice and to supply said low pressure zone without passing through said secondary orifice; a supply device and a device having a second fuel source 54 and operable to supply a second fuel to the secondary orifice simultaneously with the supply of the first fuel to the secondary orifice. a second fuel supply device having an inlet 76 in connection and communication with the second fuel source 54 and an outlet 80 in connection and communication with the fuel inlet 84; a feed pump 72 for selectively introducing fuel into the induction passage 14 through the fuel feed port;
Seed fuel supply device. 2. The two-type fuel supply device according to claim 1, wherein the first and second fuel supply devices have a common cavity 24 communicating with the secondary orifice 22. 3 the first fuel supply device is connected to the low pressure zone 18;
and a first float bowl 30 in communication with said cavity 24, and a first float bowl in communication with a first fuel source 31 and operable to control the supply of a first fuel to said first float bowl. a float regulating valve 34, the second fuel supply device being in communication with a second float bowl 52 in communication with the cavity, and a second fuel source 54, the 3. A dual fuel supply system according to claim 2, comprising a second float regulating valve (60) operable to control supply to the second float bowl. 4. The first fuel supply device includes a fuel nozzle 38 that communicates between the first float bowl 30 and the low pressure zone 18, and a conduit 46 that connects and communicates the first float bowl with the cavity 24. ,26
A two-type fuel supply device according to claim 3, comprising: